Common model reference for planning and construction

Establish a shared, georeferenced model reference from the start - most coordination mistakes happen because models are not aligned; fixing later is complicated and error-prone.

Starting point

• Discipline models often start with different origins, rotations, or height references.
• Most coordination mistakes happen because models do not share the same spatial reference.
• Shifting and updating all models later is complicated, costly, and risks inconsistencies through to construction.

Goal & benefit

• Set one binding spatial reference early for planning and construction, used by all disciplines.
• Ensure georeferencing in LV95; ideally a licensed surveyor (Geometer) delivers the reference model.
• Consistent naming of the spatial structure (project, site, building, storey) and project phase as the shared model baseline.

Process

1. Contract a surveyor and define at least three reference points within the planning perimeter.
2. Deliver the reference model georeferenced in LV95 and approve it as the binding basis.
3. Align all discipline models to it and verify alignment before coordination checks.

Outcome

• Common model reference with named spatial structure and at least three LV95 reference points as a stable basis for planning, coordination, and construction.

Deliverables

• Reference model with IfcProject, IfcSite, IfcBuilding and IfcBuildingStorey, georeferenced in LV95 (EPSG:2056)
• Name for project, site, building and storey; Phase on the project according to SIA 112
• At least three reference points as IfcBuildingElementProxy with PredefinedType=USERDEFINED and ObjectType=Bezugspunkt
• Name and Reference per point according to the survey; position and height in LV95